1. Field of the Invention
The present invention relates to a charged particle optical device for manipulating a trajectory of one or more beamlets of charged particles, in particular for use in a charged particle multi-beamlet exposure system for exposing a target using a plurality of charged particle beamlets. In addition the present invention relates to a charged particle optical device comprising such a device. In addition, the present invention relates to a method for manipulating a trajectory of one or more beamlets of charged particles in a charged particle multi-beamlet exposure system.
2. Description of the Related Art
WO 2010/125526 describes a charged particle optical device. This charged particle optical device comprises a substantially flat substrate comprising an aperture for passing said plurality of beamlets there through. The flat substrate supports the electrodes of an electrostatic deflector for deflecting said plurality of beamlets of charged particles, which electrodes at least partially and suitably largely overlies the aperture in the substrate. Said electrostatic deflector comprises a first and a second straight and elongated electrode which are arranged along the longitudinal sides of an elongated passing window, and which electrostatic deflector deflect the plurality of beamlets which pass through said window by operation of an electric field between said first and second electrodes.
As described in WO 2010/125526, the electrostatic deflection comprises a plurality of windows which are arranged in parallel. Each of said windows is relatively long to obtain maximum uniformity. In addition, each of said windows preferably has a relatively small width in order that the potential difference over the electrodes may be reduced considerably, while still obtaining a sufficient deflection angle. The advantages of such a design are described in detail in WO 2010/125526.
In the known electrostatic deflector, said elongated passing window can be arranged for passing a large number of tightly packed beamlets there through and said large number of beamlets can be deflected simultaneously.
A disadvantage of the known electrostatic deflector is that the large number of simultaneously deflected beamlets can only be deflected in a direction substantially perpendicular to said electrodes. Said beamlets can thus only be deflected in a direction substantially perpendicular to the longitudinal direction of the elongated window(s).
It is an object of the present invention to provide a charged particle optical device which can simultaneously deflect the large number beamlets in a direction substantially parallel to the longitudinal direction of said elongated window(s).